fix: update drifted file:line citations in Go patterns

Upstream golang/go has shifted several line numbers since citations
were recorded. Updated 6 citations across 3 files:

- documentation.md: server.go:55-57 → 59-62 (ErrWriteAfterFlush)
- documentation.md: transport.go:79-80 → 72-73 (Transports should be reused)
- structs.md: client.go:31-35 → 30-34 (A Client is an HTTP client)
- structs.md: client.go:59-60 → 57-58 (type Client struct)
- style.md: stream.go:280 → 292 (var _ Marshaler)
- style.md: stream.go:280-281 → 292-293 (var _ Marshaler/Unmarshaler)

Verified against golang/go HEAD (depth=1 clone).

patterns/style.md

@@ -58,7 +58,7 @@ func ParseHTTPVersion(vers string) (major, minor int, ok bool)
 // net/http/server.go:3040
 TLSConfig *tls.Config
 
-// encoding/json/stream.go:280
+// encoding/json/stream.go:292
 var _ Marshaler = (*RawMessage)(nil)
 ```
 
@@ -181,7 +181,7 @@ var _ fs.ReadFileFS = dirFS("")
 var _ fs.ReadDirFS = dirFS("")
 var _ fs.ReadLinkFS = dirFS("")
 
-// encoding/json/stream.go:280-281
+// encoding/json/stream.go:292-293
 var _ Marshaler = (*RawMessage)(nil)
 var _ Unmarshaler = (*RawMessage)(nil)